Every shipment that we send from Select Breeders Services includes an envelope of materials, zip tied to the top of the frozen semen shipper, that provides information about the semen we are sending to you. Included in the envelope are the following items:
- Transaction Report
- Safety Notice for Handling Frozen Semen
- Thawing and Handling Instructions
- Info sheet on Management of Mares with Frozen Semen
- Return FedEx airbill and address label
- Info notice regarding tank rental and return
- Additional materials may include notices prepared by the stallion owner that they have requested us to include with the shipment, e.g. breeding and insemination certificates.

When you receive your frozen semen shipment it is important to open this envelope, not just to confirm that everything is correct, but to understand the information that has been provided to you about the frozen semen and recommendations for its use. If the frozen semen shipment is sent to your vet clinic be sure to ask them for a copy of any accompanying materials that were included in the shipping container for your records. All frozen semen shipments should include some information about the frozen semen you are receiving and instructions for thawing. For frozen semen shipments sent from SBS Affiliate Laboratories, the information about the semen quality is included in the Transaction Report, we shall review this document here so you can understand and interpret the information presented.

Shipment Information

The top half of the Transaction Report (refer to sample in link) includes information related to the shipment. Across the top of the transaction report the following info is listed:

• Transaction #: Each shipment has its own transaction number, this number is a useful quick reference to identify the shipment you are referring to when calling with a particular question or concern.
• Container #: All of our shipping containers have been given a number so we can assign a tank to your shipment and to keep track of our inventory. We have a giant white board in our distribution center where we log the location (i.e. mare owner or vet clinic) of our shipping containers.
• Ship Date: This is the date the frozen semen shipment was sent out.
• Return Date: At Select Breeders Services Inc., our tank rental period is 12 days* and we include a pre-paid 3 day return FedEx airbill, therefore the shipping container is expected to arrive back at our facility 15 days after we sent it out. *Please Note: tank rental period and inclusion of return FedEx may vary at our affiliate locations.

The mare owner and information about the mare is presented at the top of the transaction report, together with the address for where the shipment was sent. Often times the shipment is sent to a veterinary clinic or mare management facility, so this section provides information to the veterinarian about which mare the semen is being sent for and who the mare owner is.

Some vet clinics have their own frozen semen storage tanks, when mare owners are calling in a frozen semen shipment request usually we will ask if the semen is going to be transferred to the vet's tanks for storage. This information is really for our own benefit, as it helps us manage our shipping containers. During the peak of the breeding season, when we are shipping multiple tanks each day, if we know a shipment of semen is being transferred to storage we can call the vet clinic and request the shipper be returned sooner.

In the "Special Instructions" section below the address is a note about late containers, if the tank is returned late there is a daily rental fee applied to the mare owner’s credit card. We request that you call us if you need additional time, since the rental time may then extend beyond the safe time period within which the shipping container can maintain temperature, therefore we may need to send you a replacement tank.

Semen Information

The bottom half of the Transaction Report (refer to sample in link) identifies the stallion and lists the semen quality information, as follows:

• Stallion/SBS ID#/Registration #/Breed: This is the stallion’s name, his SBS ID number, breed registration number and breed. The SBS ID number is a unique identifier we assign to each stallion. The first two numbers identify the lab where the semen was frozen (20 is for SBS-MD), then each stallion is assigned a 4 digit ID#.
• Date frozen: Date the semen was collected and frozen.
• No. of straws and size: The number of straws included in the shipment from each collection date and the size of the straws. Straw size is usually 5mL or 0.5mL. SBS semen frozen in the 1990s may be packaged in the 5mL size straws, now all SBS semen is frozen in 0.5mL straws (see FAQ: What Straw Size Do You Use and Why? for more information).
• Straw ID: This is the information printed on the straw that identifies the collection date, i.e. the ejaculate from which these straws were frozen. Most semen freezing labs do not own a straw printing machine (a special printer that prints all the stallion’s identifying info onto the straw); they order pre-printed batches of straws for semen freezing in advance of the collection date. It is preferable not to print the collection date on the straw, as you may not know in advance exactly what date you will collect the stallion and it may change. Instead, at SBS we use lot numbers to identify the collection date. The first collection frozen for a stallion each year is defined as Lot 01, and with each subsequent collection the lot number increases accordingly. The Lot number is pre-fixed with the collection year. Select Breeders Services in Texas owns the straw printing machine for the SBS Affiliate Network, because they can print their straws the day they need them, semen frozen at SBS Southwest has the collection date (not the Lot #) printed on the straw.
• Number of straws/dose: This tells you how many straws are in a breeding dose. For semen frozen by a Select Breeders Affiliated laboratory in 0.5mL straws, the number of straws/dose is almost always standardized to 8 straws. In the case of 5mL straws, one straw may equal one dose. When receiving non-SBS semen the number of straws/dose may vary from 1 to 10+, it is important to confirm the number of straws per dose on the transaction report that accompanies the semen, so when the time comes to breed your mare you inseminate her with the correct number of straws that constitute a breeding dose.
• Number of doses: How many doses from that collection date are included in the shipment. For SBS semen, if 8 x 0.5mL straws are included in the shipment and the # straws/dose is 8, then this shipment includes one dose of frozen semen. Depending upon the number of doses you ordered and the availability of semen, you may receive all doses from the same collection date or you may receive straws from more than one collection date that would be combined to make a breeding dose. Each collection date may vary in the post-thaw motility, so identifying the motility for each collection date included in your shipment might be important information to aid the decision of your veterinarian on which dose(s) of semen to use first, especially if there is a significant difference in the semen quality between two collection dates. When purchasing non-SBS semen you may not know what the collection date is for the semen. Some brokers purchase semen in bulk and the straws from multiple ejaculates (i.e. collection dates) are all mixed in together. If the collection date is not noted on the transaction report, look at the information printed on the straw at the time of thawing, there should be a collection date or ID code printed (or written) on the straw. This will be useful information to relay to the semen owner/agent if you have any questions or concerns about the semen quality. We recommend all breeders keep at least one of the empty straws after thawing so they have a record of what semen the mare was inseminated with should they need to refer back to it in the future.
• Post-thaw motility: This is the percentage of progressively motile sperm that was measured upon post-thaw analysis of the semen (see FAQ: How Do You Test the Quality of Frozen Semen?). At SBS we recommend a minimum of 30% post-thaw progressive motility for any semen used in a commercial distribution program. There can be considerable variation throughout the breeding industry with respect to how a post-thaw analysis is performed by a semen freezing lab. For example some labs evaluate semen visually under a microscope using their own eye and judgment; others (like SBS) utilize a computer assisted sperm analysis (CASA) system that enables a more objective measure of sperm motility. Some freezing labs may look at sperm motility immediately after thawing, whereas others (like SBS) evaluate motility after a period of incubation (30mins at 37 degrees C). There are many more opportunities for variability in the analysis, see the FAQ: Can’t Post-Thaw Motility Vary with the Laboratory Performing the Analysis?
• Number of sperm per dose, total and progressive: Most semen frozen by SBS Affiliate Labs is at a concentration of 200 million sperm per mL. Thus in a breeding dose of 8 x 0.5mL straws (= 4mL total dose volume), the total number of sperm in a dose is 800 million (4mL x 200 million/mL). The number of progressively motile sperm in the breeding dose is calculated by multiplying the total number of sperm in the dose by the percentage of progressive motility. e.g. for a sample with a progressive motility of 40%, the number of progressively motile sperm in an SBS dose is 320 million (800 million x 0.4, i.e. 40% = 40/100). The industry recommended minimum for progressively motile sperm per dose is 200 million. All doses processed by SBS Affiliate labs contain well over the minimum recommended number of progressively motile sperm per dose, particularly since we adjust the sperm concentration to 250 million/mL (i.e. one billion total cells) if the post-thaw motility for a stallion is consistently <35% progressive.
• Semen EVA status: Here we indicate the EVA (equine viral arteritis) status of the stallion. All stallions processed by SBS Affiliated Laboratories are tested for EVA before the stallion is collected for semen freezing. Equine viral arteritis is a contagious disease of horses caused by the equine arteritis virus (EAV). In most instances, horses exposed to EAV exhibit either mild clinical signs of an upper respiratory illness or no apparent clinical signs (i.e. an asymptomatic or subclinical infection). A major concern is the possibility that the virus may cause abortion in pregnant mares, illness and death in young foals and establishment of the carrier state in stallions. Carrier stallions may shed the virus in their semen for months, years or throughout their lifetime. In order to minimize the risk of infection it is recommended that mares be vaccinated against EAV before breeding with EVA positive semen, therefore it is important to know the EVA status of the semen you are receiving before breeding your mare.
• Pregnancy Data: Although post-thaw motility is a useful indicator for semen quality, it is primarily an indicator of cell health and not directly fertilizing capacity (see FAQ: Does Post-Thaw Motility Correlate with Fertility?). Fertilization is a complex process that requires numerous functional attributes of both sperm and egg. Therefore the true fertility of any frozen semen can only be determined by properly timed insemination of reproductively healthy mares. Whenever possible we try to indicate if pregnancies have resulted from the frozen semen of the stallion we are sending to you. This is useful information for your veterinarian and it may influence his decision on how best to use the frozen semen and manage your mare. 
• Processing lab: At the bottom of the transaction report it indicates where the semen was shipped from and also where the semen was frozen. If the semen sent to you was not frozen by an SBS Affiliate Laboratory a neon sticker will be attached to the bottom of the transaction report and shipment envelope to alert you to this fact. Usually we perform a post-thaw analysis of any non-SBS frozen semen we receive (by importation) before we distribute it, this will be indicated on the neon sticker.

The Transaction Report contains a lot of valuable information about the semen you are receiving to breed your mare. It is important to share this information with your veterinarian or breeding manager so they can make informed decisions on how best to manage your mare. Keeping a copy of this information on file, in addition to an empty straw, will be useful to refer to in the future should any questions or concerns arise about the semen processing and quality. As always, if you have any questions about the frozen semen you are receiving please feel free to call Select Breeders for help (410) 885-3202.

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